Answer:
homogeneous mixture means the mixture that we can't see with our naked eyes and hetergenous mixture means the particle which can't be seen with our naked eyes.
Carbon can make four bonds. Since it is doubly bonded carbon, it means it can make two more bonds. So, two more hydrogen atoms could help in bond formation.

Two H atoms are attached to each carbon.
Answer:
polar orbit is one in which a satellite passes above or nearly above both poles of the body being orbited (usually a planet such as the Earth, but possibly another body such as the Moon or Sun) on each revolution. It has an inclination of about 60 - 90 degrees to the body's equator.[1] A satellite in a polar orbit will pass over the equator at a different longitude on each of its orbits.
Launching satellites into polar orbit requires a larger launch vehicle to launch a given payload to a given altitude than for a near-equatorial orbit at the same altitude, due to the fact that much less of the Earth's rotational velocity can be taken advantage of to achieve orbit. Depending on the location of the launch site and the inclination of the polar orbit, the launch vehicle may lose up to 460 m/s of Delta-v, approximately 5% of the Delta-v required to attain Low Earth orbit. Polar orbits are a subtype of Low Earth orbits with altitudes between 200 and 1,000 kilometers.[1]
Explanation:
The answer that complete the sentence is "Arrhenius base".
The complete sentence is: A substance that increases the concentration of hydroxide ions in aqueous solution is an Arrhenius base.
Arrhenius' acid and base model says that an acid is a substance that contains hydrogen and ionizes in aqueous solution producing protons (H+) and a base is a substance that cointains hydroxide and release it in aqueous solution.
This is used for multiple scientists can perform the experiment and they can compare results.
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